The purpose of this study is to determine if arginine has an effect on IGF-1 stimulated muscle protein metabolism. After baseline measurements, a coinfusion of arginine and IGF-1 will be infused intra- arterially in one arm, while arginine alone will be infused intra- arterially in the other for a total of six hours. Repeat measurements will be made after 3 and 6 hours of the infusion. Study completed. CORE LAB ONLY.